1974 Volume 53 Issue 7 Pages 646-653
Studies on the continuous pyrolysis process of polystyrene (PS) has been carried out in order to obtain styrene monomer. The apparatus for pyrolysis were the twin screw pyrolyzer which were cosisted of a single screw furnace (PS-feeding screw), a twin screw furnace (pyrolyzer), three cooling towers equipped with reciever for liquid products and a gas meter.
Yields of styrene monomer were more than 70% at one pass under the best condition but higher molecular products called heavy oil were obtained at about 30% yields and they could be easily pyrolyzed to monomer as well as PS. The influence of pyrolysis condition on monomer yield, for example, rotation rate of twin screw, feed rate of PS, pyrolysis temperature and pitch of twin screw are discussed. It was observed that in the use of 90mm pitch screws a great deal of solid products were produced when reaction temperature was 600°C. and rotation rate of twin screw was 5-13rpm and feed rate of PS was 2.6kg/hr., though in the use of 20mm pitch screws solid products were not obtained under similar condition and even at 500°C.
